[macro-assembler] Delete unused SmiTest

Bug: v8:6921
Change-Id: Ic40a0fbf042c684f6ce8e0c4e3e8cc7cc0215fc3
Reviewed-on: https://chromium-review.googlesource.com/707243
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48526}

src/x64/macro-assembler-x64.cc

@@ -972,12 +972,6 @@ void MacroAssembler::SmiToInteger64(Register dst, const Operand& src) {
 }
 
 
-void MacroAssembler::SmiTest(Register src) {
-  AssertSmi(src);
-  testp(src, src);
-}
-
-
 void MacroAssembler::SmiCompare(Register smi1, Register smi2) {
   AssertSmi(smi1);
   AssertSmi(smi2);

src/x64/macro-assembler-x64.h

@@ -681,8 +681,6 @@ class MacroAssembler : public TurboAssembler {
   void SmiCompare(Register dst, const Operand& src);
   void SmiCompare(const Operand& dst, Register src);
   void SmiCompare(const Operand& dst, Smi* src);
-  // Compare the int32 in src register to the value of the smi stored at dst.
-  void SmiTest(Register src);
 
   // Functions performing a check on a known or potential smi. Returns
   // a condition that is satisfied if the check is successful.